Whether he was playing Peter Pan or Mrs. Doubtfire, the actor emerged as one of our most beloved father figures onscreen.

It seems entirely appropriate that my first viewing of “Aladdin” (1992) remains one of my most vivid impressions of Robin Williams onscreen, even if isn’t actually Robin Williams onscreen. Or is it? Animation, allowing for all manner of strange transformations and surreal flights of fancy, was in some ways an ideal medium for this endlessly inventive performer, and in this spirited Disney fantasy it granted him a funnyman showcase of inexhaustible cleverness and dexterity. For someone who was only 9 at the time, it also provided an early understanding of what people meant when they talked about “a Robin Williams performance.” To see and hear that big blue Genie today — morphing from one form to the next with dizzying speed, tossing off merry quips, goofy accents and fourth-wall-shattering asides — is to behold a rapid-fire comic imagination fully liberated from the dull, colorless parameters of live-action. Here, at last, was a movie that could keep up with this guy.

“He even looks like Robin Williams!” I remember a friend marveling when she saw the first images of the Genie on TV — and indeed he did, the Disney animators having slyly modeled the character’s friendly grin and elastic, exaggerated gestures on the actor’s own. Williams famously improvised much of his dialogue — an unusual thing for an animated picture, where vocal work is typically subordinate to images and screenplay. But the honchos at Disney must have recognized that it would be foolish to try and contain their star’s vaudevillian instincts, any more than a lamp could contain the Genie himself. “Aladdin” is hardly the first or only film in which Williams upstages just about everything and everyone else onscreen, but the sheer force of his big-hearted personality doesn’t smother the movie; it completes it. This Genie is more than a hilarious show-off. He’s a fount of wisdom, a voice of conscience to rival Jiminy Cricket, and one hell of a sweet guy.

The following year brought along a movie that would prove no less emblematic of who Robin Williams was as a screen performer. I’m speaking, of course, about “Mrs. Doubtfire” (1993), a ruthlessly effective slapstick tearjerker that thoroughly worked me over, to say nothing of thousands of other moviegoers: With the invaluable support of a fat suit, a wig and a cream pie, Williams’ Mary-Poppins-meets-Tootsie routine succeeded in making my 10-year-old self laugh and cry on cue as advertised. I don’t know if my 31-year-old self would call it a great movie, but it is an indelible one, and for a high-concept comedy vehicle, it cuts unusually close to the bone. For anyone who hears two parental voices raised in anger and can’t help but flinch in recognition, the movie has a particularly sharp, lacerating power: The air of familial discord is so persuasively realized that it gives Williams the emotional ballast he needs to pull off one of his most improbable, and improbably successful, characterizations.

It doesn’t hurt that Mrs. Doubtfire herself, far from being just a grotesque stunt, instead becomes a warm, lovable creation in her own right, with a delicacy of manner and an elegance of carriage that remind you, for all his antics, what a subtle, even graceful actor Williams could be. But the conviction of the performance goes deeper than that: Even the character’s most reckless, elaborate machinations seem to well up from a painfully honest place of love for his family, as if he could only restore domestic order by descending into farcical madness. What sort of lunatic would go to such extreme lengths for his children? Probably no one, hopefully — but for two hours, Williams has a grand time making you think otherwise.

How many times has Robin Williams played a father or father figure onscreen? Without oversimplifying a body of work that has no use for tidy parameters, it’s this tendency that has long struck me as one of the defining impulses of his work — the desire to give shape and form to a highly eccentric form of fatherhood, to play a mentor to the young and impressionable, and to draw upon his comic genius as a way to take us deeper into ourselves. It was there the first time I saw Williams onscreen, in “Hook” (1991), where he played a grown-up Peter Pan who desperately needs to reconnect with his children and his own inner child. It was there, too, in “The Birdcage” (1996): As a gay dad trying to maintain an illusion of heterosexual propriety for the sake of his son, Williams underplayed beautifully, leaving the flamboyant antics largely to Nathan Lane while serving as the movie’s emotional glue.

The forgettable mainstream comedy “RV” (2006) is unlikely to rank high on anyone’s list of favorite Robin Williams movies, but it, too, finds the actor playing a much-put-upon dad (“Save for one out-of-nowhere gangsta-riff monologue, this is one of Williams’ least shtick-reliant performances,” I wrote in my Variety review). And the perils of fatherhood form the crux of Bobcat Goldthwait’s aptly titled “World’s Greatest Dad” (2009), a woefully underseen, darkly funny gem that features one of Williams’ last and greatest screen turns. In it he plays a loving father to a horribly unlovable son who dies accidentally, via auterotic asphyxiation, a premise that takes the Robin Williams fatherhood complex to audacious new extremes of perversity and profundity.

Williams’ paternal roles seem rooted in an essentially therapeutic instinct — the notion that we could, by spending some time in the company of one of his characters, feel loved, understood, and inspired to live better, happier, more fulfilled lives. The role of therapist is quite literally built into a number of Williams’ best-remembered characters — from his embodiment of a nerdy, devoted Oliver Sacks type in “Awakenings” to his Oscar-winning turn as a psychiatrist in “Good Will Hunting” — and also one of his worst-remembered, the physician-clown who gave the widely reviled yet hugely successful “Patch Adams” its title. He was considerably more enduring, and endurable, as the English instructor John Keating in “Dead Poets Society,” applying a gentle sense of showmanship to his lessons in life and literature. I think it’s a meretricious, dishonest movie, but there’s nothing dishonest about the performance, which really is stirring enough to warrant its famous valediction of “O captain, my captain.”

The critic is trained early on, of course, to disdain the cinema of inspiration and self-improvement, and also to dismiss any actorly weakness for incessant shtick or overt sentimentality. And there’s no denying that, as his career progressed and he seemed to lapse into predictable rhythms and cycles of onscreen behavior, Robin Williams became something of a punching bag for reviewers — a too-convenient stand-in for the worst kind of Hollywood button-pushing, veering forever between the twin extremes of over-the-top comedy and lump-in-the-throat emotionalism. It wasn’t always a fair accusation, but you could understand the feeling behind it, especially when it became clear that the actor himself was trying to press his talents in a different direction.

So memorable and outsized was Williams’ persona that even his later stabs at restraint could sometimes announce themselves a bit too loudly. In some of his late-’90s and post-’90s efforts, you could sense the actor studiously tamping down every twitch, smile and wayward comic impulse in a sometimes honorable, sometimes misguided bid for seriousness, almost as if he were doing penance for having entertained us too heartily in the past. But even here, Williams the guardian persists, sometimes benevolently — see him trying to inspire his fellow prisoners in the Holocaust drama “Jakob the Liar” — and sometimes not. One way to read the devious stalker Seymour Parrish in “One Hour Photo,” easily the strongest of his self-consciously “serious” turns, is as the disturbing inversion of all those smiling, pure-hearted father figures. Here is Williams the creepy, asexual loner, quietly monitoring a family from afar, eager to step in and restore order and balance when the real father falls short.

A performance like that is a sign of a career rich and varied enough to mean different things to different people. In looking back on their favorite Robin Williams roles, some will gravitate fondly toward his turn as a genial madman in “The Fisher King,” or his manic yet beautifully controlled performance as an army shock jock in “Good Morning, Vietnam.” “Mork & Mindy” was before my time, but not my mother’s (“Nanu nanu,” she murmured with a sad chuckle when she called me yesterday afternoon to talk about Williams’ death). I’ll remember him as the actor who revealed the funny side of fatherhood, who came most unpredictably to life when he was sharing the screen with children, and who proved that a grown man could be the youngest guy in the room. We really never had a friend like him.

Mrs.Doubtfire was,make NO mistake ,a great performance by Robin.But there is another,much earlier “father” role of his which resonates on a deeper level ,to this day.That being the title character in the film adaptation of John Irving’s The World According to Garp”.A scene in particular stands out-with and his first & only true love-“Jenny” (portrayed to the T )by the astonishing Mary Beth Hurt.Garp,contemplative and restless,is reminiscing about “the arc of your life”- is aware of their growing drift & suddenly tenuous hold on the future.He jumps out of bed ,quietly imploring Jenny “let’s go have a look at the kids” as they lay dreaming,unaware of the pride,and the awe he had, for his role as their father.Oh Robin,you revealed more of yourself in Garp than you realized.Farewell dear friend.